application is central remote sequenced startup and shutdown for multiple amplifiers (in my case 4 or 6) and dac/s (for me 2 balanced dacs with possible integration of a 3rd) via solid state relays and possibly with the addition of volume control, as both sabre dac and the wolfston discussed here will allow volume.
then we are also as well discussing the possibility some monitoring of case/heatsink temps. then LCD display to reflect this information and ADC for linear voltage to digital conversion.
and btw i'm seeking feedback from the wider group of participants as to whether any of this has value to them, rather than just rambling on for my own needs when it doesnt match the wants of the group
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There are port expanders for i2c. It may be useful to look over amb's lcduino project The LCDuino-1 Display I/O Processor. It is doing a lot of what you guys are talking about - delayed trigger for a SSR, communication via i2c and port expanders, RF input, lcd display. Source code is available by request.
@qusp what voltages are you interested in sensing with the ADC?
@bcg27 I've looked at the lcduino and hifiduino projects and while I like their ideas, I want something a bit more specific. For example I need more than one relay in my system (3 to start with, more later).
I too would like feedback on what parts of the stuff that we've talked about would be of any use to people running these amps? Since, like qusp and I have said, they're likely used in active systems are people either a) leaving them on all the time? b) manual on/off sequencing? c) already got their own solution they're happy with?
For me on/off sequencing is critical because the minidsp that I use makes some shocking noises if turned on after the amps are on. I will likely have my controller inside the same enclosure as minidsp and trigger outputs wired from there to each amplifier. If we want temp sensing then we need a micro in every amplifier and rs232/ethernet/i2c comms to the display (I don't want an lcd on every power amp). Eventually I'd like to have separate descrete dacs instead of those internal to the minidsp ... you can see how I'll have a nightmare if I try switching all of these on in a specific order along with 6ch of power amplifiers. Then I'd have to explain to my wife why she has to do it all in a certain order. 😱
I'm ok with writing some code once we know what the goal is and sharing it if others may find it useful.
yeah i had thought about contacting linuxguru about this, thought there was such a thing as a port expander as it would seem a bit archaic and expensive to have to have a separate arduino for each monitoring task. however i dont think we need it to be so flexible and as a result a bit ungainly. i only want a limited number of parameters controlled, i dont need the equivalent of an audio amplifier rectal probe.
hochopeper: the ADC is for volume control, so i can use an actual knob so a linear pot, like the volumite is fed a 3v3 voltage and the output fed to an ADC which communicates the level with the dac
sounds like your needs and mine are pretty well aligned i'm just a little further down the track. while i'm only having a 2 channel (4 channel) system its relatively uncomplicated to control the volume of the dacs as there is 2 i2c addresses in the sabre, once i go 3 way there would need to be some sort of external MCU to help
hochopeper: the ADC is for volume control, so i can use an actual knob so a linear pot, like the volumite is fed a 3v3 voltage and the output fed to an ADC which communicates the level with the dac
sounds like your needs and mine are pretty well aligned i'm just a little further down the track. while i'm only having a 2 channel (4 channel) system its relatively uncomplicated to control the volume of the dacs as there is 2 i2c addresses in the sabre, once i go 3 way there would need to be some sort of external MCU to help
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I wasn't saying the lcduino does everything you want, just that it seems like a very good starting point and would have a lot of the coding done for you already. Same with the hifiduino, which I am not as familiar with. Looking over the description really quickly though it seems like if you can frankenstein parts of the lcduino together with the hifiduino they do everything you want between the two of them except maybe the temperature stuff. And sequencing a series of 5 V outputs to control SSRs should be trivially simple as long as you have enough outputs.
lcduino does what you want qusp. It will even use a motorized pot so if you control volume with the remote it will turn the knob
lcduino does what you want qusp. It will even use a motorized pot so if you control volume with the remote it will turn the knob
hey its all good bcg27, i appreciate the suggestion, already knew of his efforts and you are probably right, if we could gain access to the code we could lift sections and leave others. I do wonder however, given the fairly low number of tasks, whether it might be just as quick to start from scratch. but then i know literally nothing about programming an arduino, so i'd be happy to be wrong.
the main thing for me is sequenced start up and shutdown as well as display and maybe monitor temp, the rest is icing as i have much of it elsewhere in the system, but i would ideally like all of it in the one place with the one control, remote would be nice eventually
the main thing for me is sequenced start up and shutdown as well as display and maybe monitor temp, the rest is icing as i have much of it elsewhere in the system, but i would ideally like all of it in the one place with the one control, remote would be nice eventually
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You'll find plenty and all sorts of I2C devices with google.
I2C potentiometer
I2C temperature sensor
I2C Relays
I2C LCD Displays
I2C Keyboard
I2C Touch Pad
I2C Touch Screen
And many more I2C devices
Most are hardware, some run a small simple software.
I2C Central Unit this will run the main software. To choose for ease of programming and software support.
All of these devices are communicating on a 3 wire bus SDA SCL Ground. Some add a 4th wire to provide 5v or 12v to devices
A device is configured as master the others as slaves. Each slave is configured with a different adress.
There are 2 types of data transfers. Both are initiated by the master. Transfer from Master to Slave and Transfer from Slave to Master.
I2C is multi master capabable but it is much easier to stay away from this, there is rarely a real need for it.
I2C is fine as long as you don't need fast data transfers neither long distance.
I2C potentiometer
I2C temperature sensor
I2C Relays
I2C LCD Displays
I2C Keyboard
I2C Touch Pad
I2C Touch Screen
And many more I2C devices
Most are hardware, some run a small simple software.
I2C Central Unit this will run the main software. To choose for ease of programming and software support.
All of these devices are communicating on a 3 wire bus SDA SCL Ground. Some add a 4th wire to provide 5v or 12v to devices
A device is configured as master the others as slaves. Each slave is configured with a different adress.
There are 2 types of data transfers. Both are initiated by the master. Transfer from Master to Slave and Transfer from Slave to Master.
I2C is multi master capabable but it is much easier to stay away from this, there is rarely a real need for it.
I2C is fine as long as you don't need fast data transfers neither long distance.
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Thanks mchambin and bcg27 for the pointers! I have a better picture of how this will fit together now. Like bcg27 says this really is a mash up of those 2 projects, except for in my system I'm also adding interface to a denon receiver and xbmc pc via ethernet, I doubt any others here are interested in that part though!
Ah ok I'd previously thought that I'd make something similar to a volumite but with rotary encoder rather than analogue input from a pot. I'd never even looked at the schematic for the volumite though, this could be simpler to implement.
Agree we can make it simple to start with and add bling later 😀
So with temps do you want to have them visible/accessible all the time or just have overtemp warning/shutdown settings? In an ideal world I'd like this to be network connected and have some sort of webinterface, that could be a lot of work though!
With the display on the controller for my system I was thinking something along the lines of the m2tech young frontpanel - Young DAC
Ah ok I'd previously thought that I'd make something similar to a volumite but with rotary encoder rather than analogue input from a pot. I'd never even looked at the schematic for the volumite though, this could be simpler to implement.
Agree we can make it simple to start with and add bling later 😀
So with temps do you want to have them visible/accessible all the time or just have overtemp warning/shutdown settings? In an ideal world I'd like this to be network connected and have some sort of webinterface, that could be a lot of work though!
With the display on the controller for my system I was thinking something along the lines of the m2tech young frontpanel - Young DAC
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Hmmm, I never realised how useful the arduino based products could be in an application like this. I'm also building a minidsp based setup and getting rid of the ridiculous turn-off pop is an issue...
Very interested to see what you guys come up with.
Haven't had much time to work on a chassis design as I'm really busy at work. I'll make time regardless once a basic layout is agreed upon.
Just out of interest, what would the slew rate be of the lpuhp?
Very interested to see what you guys come up with.
Haven't had much time to work on a chassis design as I'm really busy at work. I'll make time regardless once a basic layout is agreed upon.
Just out of interest, what would the slew rate be of the lpuhp?
FAST!! the slew rate of the amp is basically the slew rate of the lme buffer, which is 2000V/us
ok so i think we've pretty much decided on a blank front except for perhaps the option for am LED and small momentary (though we may even get rid of that with arduino, should probably still be an option.
dont hate me for asking this and i do not intend to complicate things here, just asking. but if we are able to decide on a basic set of ins and outs, you do these one at a time anyway right? say there is a group that is happy with arduino control and thus would only need an LED on the front, with perhaps a manual override on the back and then another sub-group who intend to use it on its own have a single momentary; would it present any difficulty other than having 2 cad files one with and one without. that being the only difference; ie nothing that might require a different setup, or clamping etc.
i am absolutely not wanting to open the door for doing changes for everyone, but I would think something as straight forward as that wouldnt cause you trouble?
so what do you need from us? i will go about trying to orchestrate working towards making it happen. there is something to be said for having the PCB in hand before finalizing it anyway, but i understand yours is on the way also? i know mine and hochopeper's is as of today.
ok so i think we've pretty much decided on a blank front except for perhaps the option for am LED and small momentary (though we may even get rid of that with arduino, should probably still be an option.
dont hate me for asking this and i do not intend to complicate things here, just asking. but if we are able to decide on a basic set of ins and outs, you do these one at a time anyway right? say there is a group that is happy with arduino control and thus would only need an LED on the front, with perhaps a manual override on the back and then another sub-group who intend to use it on its own have a single momentary; would it present any difficulty other than having 2 cad files one with and one without. that being the only difference; ie nothing that might require a different setup, or clamping etc.
i am absolutely not wanting to open the door for doing changes for everyone, but I would think something as straight forward as that wouldnt cause you trouble?
so what do you need from us? i will go about trying to orchestrate working towards making it happen. there is something to be said for having the PCB in hand before finalizing it anyway, but i understand yours is on the way also? i know mine and hochopeper's is as of today.
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Great news on the pcb front qusp!
That backpanel is getting hectic! Fused IEC + maybe switch, xlr/lemo/rca, binding post and maybe 5/6 terminal OR a 4 terminal and a 2 terminal socket(s) for i2c sensors and relay control. I think we're really getting too flexible on the back panel if we have options for all of that. Is there some way to
The idea I had in mind for standardised front panel would be to have an illuminated switch hooked up in a way that if we're switching manually or by relay the LED still gets lit.
That backpanel is getting hectic! Fused IEC + maybe switch, xlr/lemo/rca, binding post and maybe 5/6 terminal OR a 4 terminal and a 2 terminal socket(s) for i2c sensors and relay control. I think we're really getting too flexible on the back panel if we have options for all of that. Is there some way to
The idea I had in mind for standardised front panel would be to have an illuminated switch hooked up in a way that if we're switching manually or by relay the LED still gets lit.
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I think having the front panel with a cutout for a momentary can be pretty universal. My favorite are the bulgin ones like this MPI002/28/BL Bulgin Pushbutton Switches although you can find similar ones from other brands for much cheaper.
Since they have an led in them if you go with arduino power on/off you could leave the switch part unwired and just wire the led. Obviously a bit more expensive than a $0.10 led, but it would mean just 1 front panel.
edit: I see hochopeper beat me to it 😛
Since they have an led in them if you go with arduino power on/off you could leave the switch part unwired and just wire the led. Obviously a bit more expensive than a $0.10 led, but it would mean just 1 front panel.
edit: I see hochopeper beat me to it 😛
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I have a bulgin switch in my other power amp already so that was where I was going too. I'd actually wire the switch in series with the relay and leave it always in on position for emergency situation where I need to hit all the buttons in a hurry to turn them off. Also if I pass out on a Friday night and someone else is not familiar with the system can just hit the off button and get the expected outcome.
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bulgin? meh...check out the APEM range. i prefer a discrete LED personally, those bulgins are everyfrackinwhere
the blank round one is piezoelectric, finger touch sets it off, no mechanism, its going on the dac the other one is an APEM too, as is the diffused white LED. nice stuff
the blank round one is piezoelectric, finger touch sets it off, no mechanism, its going on the dac the other one is an APEM too, as is the diffused white LED. nice stuff
Attachments
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now you see, if we didnt have to standardise, we could have ALL of that except for the speaker outs on a 25 or 50 pin Dsub and make the mother of all breakout cables
as a result it would save quite a bit of money too
edit: with mono we would only need a 9 pin or max 25 to spread the pins out a bit. you can get some pretty nice milspec ones from amphenol for not much money
subvert the dominant paradigm!!
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You definitely don't want to wire one of the momentary switches in series as they are typically only rated for a few tens of mA. You can get latching ones, of which the highest I have seen is 5A. IMO for a power amplifier that is a bit low, although it may be ok for one this low powered. Granted you will never be pulling 5A continuously but turn on surge into the capacitor banks of your power supply could easily be higher than that for brief periods, which may damage the switch over time.
Piezoelectric is cool qusp, I will take a look at those. I do like the Bulgin though.
Piezoelectric is cool qusp, I will take a look at those. I do like the Bulgin though.
PUSHBUTTON SWITCH DPDT ALTERNATE 12V BLUE-MPJA, Inc.
...also available in red, green & yellow
@ $6.95
I would be wearing the brown shoes in this black tie affair. 😀
...also available in red, green & yellow
@ $6.95 I would be wearing the brown shoes in this black tie affair. 😀
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haha Ed, dont mind me, i've been collecting special bits and pieces for this system for a couple of years as i find them and its finally all coming together.
I have a dream....
bcg27: dont you dare get it!! never seen anyone else use one lol. nah actually i think even bulgin has a similar, but not as clean looking (love the iconic look) piezo one as the no moving parts fits with the whole vandal proof thing. cant remember what i paid for these 2, think the piezo was a bit less than $40 and the other closer to 50. the pushbutton one is rated for a fair bit of current, but i dont think the intention, certainly not my intention; is to actually switch any current with these, but simply hit the SSR with a control voltage
I have a dream....
bcg27: dont you dare get it!! never seen anyone else use one lol. nah actually i think even bulgin has a similar, but not as clean looking (love the iconic look) piezo one as the no moving parts fits with the whole vandal proof thing. cant remember what i paid for these 2, think the piezo was a bit less than $40 and the other closer to 50. the pushbutton one is rated for a fair bit of current, but i dont think the intention, certainly not my intention; is to actually switch any current with these, but simply hit the SSR with a control voltage
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